MONDAY, Jan. 13, 2014 (HealthDay News) -- Those little bundles of joy aren't always tickets to happiness, as most parents know. But a new study suggests that middle-aged parents in the United States living with younger children are no more satisfied or happy than childless people.

The study isn't a definitive take on the well-being of adults with and without children. Still, it does suggest that people tend to make the right personal decisions about parenthood, said study author Angus Deaton, professor of economics and international affairs at Princeton University in New Jersey.

Within the limits of the study, "there's no big difference in life satisfaction between those who have kids and those who don't once you take into account their various life situations," he said. "Some people say you really can't be happy if you don't have kids. We think that doesn't make a lot of sense. People who have kids by and large are those who want them."

Why try to figure out the life satisfaction associated with parenthood? It's an important question "because media has often portrayed parents as miserable," said Sonja Lyubomirsky, a professor of psychology at the University of California, Riverside, who studies happiness and is familiar with the new study.

For the study, published in this week's issue of the Proceedings of the National Academy of Sciences, Deaton and a colleague analyzed 2008-2012 surveys of 1.77 million people in the United States. The Gallup organization conducted the surveys, which asked participants about their lives and daily emotional experiences. The researchers also looked at similar global surveys that asked questions of about 1 million people from 161 countries.

The researchers focused on people aged 34 to 46 with kids under age 16 living at home. Compared to others in that age range, this group was more satisfied with their lives. But the groups were about equal after the researchers adjusted their statistics so they wouldn't be thrown off by factors such as income and education, which are both linked to a greater likelihood of having children.

The study is careful not to assume that people automatically want kids. "Those without children are not failed parents, and those with children are not failed nonparents," it stated. Deaton puts it this way: "If I wanted kids and couldn't have them, that sure would do bad things to me. But if I didn't want kids and got one because a stork happened to fly by, that wouldn't make me happy ... People sort of get what they want."

The researchers also discovered that middle-aged parents of younger kids had higher highs and lower lows than everyone else. "Kids are fun, but they come with worries and anxieties," Deaton said.

It's not clear from the study whether the joys of having adult children and grandchildren push parents past others on the happiness meter. Nor is it clear how freedom from kids might contribute to happiness.

Lyubomirsky, the happiness researcher, praised the study and said it is well-designed. She's especially intrigued by statistics about the link between parenthood and life satisfaction in the rest of the world.

Deaton found that parenthood is linked to less life satisfaction in other parts of the world outside the richer, English-speaking countries.

"I would love to see more research trying to understand why parents in high-fertility countries are relatively less happy," Lyubomirsky said.